Air Play Mirroring

Air Play mirroring will feature 1080p wireless screen sharing but you must have Apple TV.

Game Center

The popular gaming platform is now coming to the Mac. See which of your Mac games are Game Center enabled and find friends/foes in your gaming network.

Power Nap

Power Nap keeps your Mac up to date and backed up while it sleeps.

Documents In The Cloud

Documents in the Cloud brings greater integration of iCloud to the Mac.

Apple's new iCloud solution offers the advantage of displaying only those files intended for use with the app being used, helping to filter the list of documents and offering iOS-like folder organization of files.

Reminders

The popular iPhone app now brings cross compatibility to the Mac. Save a reminder on your iPhone/iPad and it shows up across all devices.

Messages

Messages bring iMessages to your Mac and support across all Apple devices.

Notification Center

Notification Center brings alerts to the Mac. Notification center will let you know when you have an unread email or when an app needs to be updated.

There is also a feature to turn off notifications, and if you connect your Mac to a projector notifications get disabled automatically.

Dictation

Everywhere on your Mac where you can type, you can talk.

"You can talk into Facebook if you want."

iCloud Tabs

iCloud tabs shows all the pages you have open across all devices.

This brings a very iPad-like experience to the desktop when navigating the web.